Evolution of the
Holocene Carbonate Ramp Complexes of Southern Kuwait
Lomando, A. J.1, E. Gischler2,
A. Al-Dharmi3, T. Al-Adwani3 (1) ChevronTexaco,
Kuwait, San Ramon, CA (2) Univ. of Frankfurt, (3) Kuwait Oil Company, Kuwait
onshore southern Kuwait
contains a complete carbonate ramp suite from outer-ramp muds
and mid-ramp reef buildups to inner-ramp ooid
shoal-beach-dune systems and backshore tidal flats and sabkhas.
The modern coastal system is the site of shoal and tidal channel–delta ooid factories that feed the beach systems. These
factories, in turn, have fed an extensive coastal beach dune-ridge complex for
the past 6000 years. From southern Kuwait
into northern Saudi Arabia,
shallow folds and faults perpendicular to the regional coastline strike create
a series of headlands and intervening cuspate reentrants with periods of 20 to
50 kms. Depositional packages include long, narrow oolite dune-ridge complexes in reentrants and wide oolite ridge strand plains down current of each headland.
Inter-ridge fills are a combination of wind-blown reworked ooids,
very fine quartz sand, gypsum crystals, and clay dust derived from the upwind
deserts of Iraq and Syria.
Biogenic structures in the dunes are most commonly rhizoliths
and rare insect and mammal burrows. Complex progradational
units formed during high-frequency, low-amplitude Holocene sea-level cycles.
Rare complete exposures have been vertically measured and age dated from their
skeletal-ooid beach and shoreface
deposits up through the aggrading, overlying oolite
dunes. This has permitted construction of a calibration curve using elevation
and the time difference between the establishment of the shoreline and the
formation of oolite dunes above them. Thus,
respective shoreline ages can be established from dune ages of known elevation
when exposures are incomplete. Mapping dated groupings of oolite
ridge complexes combined with satellite imagery have permitted the Holocene progradational history to be subdivided into Bronze, Iron,
and Arab age high-frequency Holocene progradational